Functional Resolution

Functional Resolution:


The Functional Resolution is the frequency at which the SFR amplitude equals the Discernment Limit (typically 10{87544f4b958fce1c89be16ae80d8737220922657377564151bb9b966540e4285}).  Detail in an image that has a higher frequency than this “limiting frequency” is not easily distinguished by the average human observer. 

Measurement Details:

The Functional Resolution is computed using these steps:

  1. Calculate the horizontal and vertical SFR curves
  2. Determine where the SFR amplitude for the Visual curve equals the Discernment Limit.
  3. Compute the average of the horizontal and vertical frequencies.




The unacceptable functional resolution image has equal sensor resolution (50 dpi) as the acceptable image but much lower optical efficiency (50{87544f4b958fce1c89be16ae80d8737220922657377564151bb9b966540e4285}).  The resulting functional frequency (27 dpi) is below specification (35 dpi).





Both the discernment limit and minimum functional resolution are required to specify functional resolution. These are accessible in the Functional Resolution tab.  A conversion tool is available to calculate resolution units from dpi.